Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

Migrants rush as they try to get on a train heading to the border with Serbia at the train station of Gevgelija, on the Macedonian-Greek border, on August 9, 2015. Non-EU Serbia's frontier with Hungary, which is in the bloc's passport-free Schengen zone, has become a major crossing point for the huge numbers of migrants entering the EU. (Photo by Dimitar Dilkoff/AFP Photo)

Model Bella Hadid has her make-up done inside Blenheim Palace ahead of a fashion show presenting the Dior, Cruise 2017 Collection, in Woodstock, Britain May 31, 2016. (Photo by Dylan Martinez/Reuters)

“Benito Amilcare Andrea Mussolini (29 July 1883 – 28 April 1945) was an Italian politician who led the National Fascist Party and is credited with being one of the key figures in the creation of Fascism”. – Wikipedia

Photo: Italian fascist dictator Benito Mussolini leads his officers in a spirited run in full military regalia. (Photo by Keystone/Getty Images). Circa 1940

An elephant decorated with a cloth walk in the annual Perahera (street pageant) at Rajamaha viharaya Buddhist temple in Colombo, Sri Lanka September 10, 2016. (Photo by Dinuka Liyanawatte/Reuters)

Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

Child models present creations at Dong Wenmei T100 Children's Collection during China Fashion Week in Beijing October 29, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A woman is cooled down with a watering can as she sunbathes using insulating tape, at a beauty center in Belo Horizonte, Brazil, on December 21, 2017. Brazilian women take advantage of the beginning of the summer to sunbathe using the new national trend: natural tanning with insulating tape. Instead of using tiny bikinis on the beach, women avoid being bothered or stalked by getting taped in the shape of them, and lay in the sun over rooftops to enjoy the morning sun and get the perfect “marquinha” tan lines. (Photo by Douglas Magno/AFP Photo)